CALOSTAT® owes its internal structure to its main component, amorphous (non-crystalline) synthetic silicon dioxide. This material, also commonly known as silica, was invented by Degussa more than 80 years ago and has been produced in its basic form since the 1950s. The high-purity material is found in many products such as paints, toothpastes, cosmetics, and food.
Unique production processes give CALOSTAT® special new properties. These include, most importantly, an optimized porosity made possible by a special solid structure with perfectly balanced low density. The pore volume and solid structure enable a variety of delivery forms. At present CALOSTAT® is available in a number of sheet types and as a granulate. During production the material is hydrophobized deeply into the pores. So that while it cannot absorb liquid water it remains permeable to water vapor. Both the material and the production process are protected by multiple Evonik patents.
All sheet and granulate forms of the new material have been optimized for use in insulation. All the three pathways for heat transfer have been efficiently restricted. Conduction through the solid is minimized by maximal reduction of contact points in the amorphous silica matrix and by the internal structure. There is very little movement of gas molecules in the small pores, so that heat transfer through gaseous motion is also minimized. And, thanks to its composition, the material can absorb radiant heat effectively. Taken together, these factors result in a λ-value of just 0.019 W/mK. By way of comparison, stationary air has a λ-value of 0.026 W/mK. Therefore, CALOSTAT® is designated a superinsulation material.
CALOSTAT® is admired as an insulation material because it is inherently non-flammable. In the construction industry, CALOSTAT® sheets are used mainly in the building envelope. They are also used in other industries, as shipbuilding, machine and plant engineering, and fire protection. CALOSTAT® granulate is highly effective as an insulating filler in complex closed geometries and as the main component of formulations for composites for dew point shift, as well as for safe touch surfaces and energy saving.
Along with aerogels, CALOSTAT® has been classified in the Advanced Porous Materials group by the Energy in Buildings and Communities (EBC) Programme of the International Energy Agency (IEA). Due to the outstanding insulating properties of this superinsulation material, the EBC sees in it strong advantages compared with conventional insulating materials, particularly in view of global efforts to save energy in order to meet the targets of the Paris Agreement on climate change.
Evonik is a founding member of the Advanced Porous Materials Association (AdvaPor), a global association for promoting dialog and exchange between producers, users, researchers, and other industry professionals interested in, or already working in, this exciting area.